Fix htg io xml
Superseed !11038 (also rebased).
Description:
vtkXMLHyperTreeGridWriter takes DepthLimiter parameter of HyperTreeGrid into account only for version 2 of file output.
Extension of testing to cover this aspect of write reduction.
/Common/DataModel/vtkHyperTree.cxx
/Common/DataModel/vtkHyperTree.h
/Documentation/release/dev/fix-htg-xml-io-reader.md
/IO/XML/vtkXMLHyperTreeGridWriter.cxx
/IO/XML/Testing/Cxx/TestXMLHyperTreeGridIOReduction.cxx